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2Addicts | BMW 2-Series forum Technical Topics N55 (M235i) Engine, Transmission, Exhaust, Tuning URGENT,,N55 M235i Super Knocking in cylinders, please help!

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      09-10-2021, 02:37 AM   #1
RyanSira
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URGENT,,N55 M235i Super Knocking in cylinders, please help!

I have a 2016 BMW M235i I'm running a stage 2 bootmod3 OTS tune. I'm FBO with a dorch HPFP stage 1. I am getting super knocking in multiple cylinders after 4 consecutive pulls last night.
I'm getting fuel injector shut down and super knocking. I don't know if I need to tow it or drive it to the shop. I have a ARM charge pipe and I'm thinking maybe it could've blown off. But also I just got my HPFP installed last week and not sure if it failed. It still starts fine and honestly drives normally you can only feel it at idle, it idles really rough and feels like really bad misfires. Just really worried about it, thank you for the responses in advance.
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      09-10-2021, 03:14 AM   #2
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I was thinking about just resetting and clearing the codes on bootmod3 and seeing if it's just reading the codes from the pulls and is running weird from that. I'm fearing the worst and hoping it's something simple.
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      09-10-2021, 12:51 PM   #3
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Read the codes on the bm3 app in Diagnostics. It should tell you if a particular cylinder(s) are misfiring. Check plugs and coils first (switch the coil to another cylinder and check if the code moves; if it does change out that coil). I had the same thing and it was a leaking injector. Changed that out and all is well (I changed out the plugs first but that didn't change anything).
Good luck.

Chris
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      09-10-2021, 01:42 PM   #4
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Quote:
Originally Posted by Efftooto View Post
Read the codes on the bm3 app in Diagnostics. It should tell you if a particular cylinder(s) are misfiring. Check plugs and coils first (switch the coil to another cylinder and check if the code moves; if it does change out that coil). I had the same thing and it was a leaking injector. Changed that out and all is well (I changed out the plugs first but that didn't change anything).
Good luck.

Chris
Thank you so much, I'll try that. I think I'm going to flash back to stock first because I don't wanna push it too hard. I have to drive it to the shop still.
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      09-10-2021, 03:46 PM   #5
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Pardon the seemingly dumb question on my part, but I assume you do have at least 1 step colder spark plugs?

Running fbo, extra fueling capacity, and stage 2 bm3 tune, I have to strongly suggest you do if not already.
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      09-10-2021, 03:49 PM   #6
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Originally Posted by MLJR235 View Post
Pardon the seemingly dumb question on my part, but I assume you do have at least 1 step colder spark plugs?

Running fbo, extra fueling capacity, and stage 2 bm3 tune, I have to strongly suggest you do if not already.
I do not have step 1 folder plugs, I was never told to get them and never thought they'd make that much of a difference
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      09-10-2021, 03:59 PM   #7
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Quote:
Originally Posted by RyanSira View Post
I do not have step 1 folder plugs, I was never told to get them and never thought they'd make that much of a difference
Yeah, it's pretty important . Pushing anywhere from 75-100hp over stock, you are likely in that range, it is recommended to go 1 step down in spark plug heat range.

You probably got the stockers too hot after those consecutive runs and well, super knock reared its ugly head.

As said before, pull the plugs you have now and check for damage first before you start driving it around.
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      09-10-2021, 04:27 PM   #8
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If there are any pepper-like flecks on the spark plugs or indication of the plug tips melting, it is advisable to get a fibre optic camera through the spark plug holes into the bores to check for localised melting of the pistons due to pre-ignition, too.
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      09-10-2021, 07:15 PM   #9
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Quote:
Originally Posted by MLJR235 View Post
Quote:
Originally Posted by RyanSira View Post
I do not have step 1 folder plugs, I was never told to get them and never thought they'd make that much of a difference
Yeah, it's pretty important . Pushing anywhere from 75-100hp over stock, you are likely in that range, it is recommended to go 1 step down in spark plug heat range.

You probably got the stockers too hot after those consecutive runs and well, super knock reared its ugly head.

As said before, pull the plugs you have now and check for damage first before you start driving it around.
Well guys I think I got it figured out. You were right 100%. Those damn plugs were so melted they weren't even gapped anymore lol. I ordered step 1 colder plugs hoping that fixes the issues completely. Hoping it didn't do any damage from them getting really hot
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      09-10-2021, 10:09 PM   #10
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Quote:
Originally Posted by RyanSira View Post
Well guys I think I got it figured out. You were right 100%. Those damn plugs were so melted they weren't even gapped anymore lol. I ordered step 1 colder plugs hoping that fixes the issues completely. Hoping it didn't do any damage from them getting really hot
Hi, you most likely have gas with too low of octane and are getting detonation that melted the plugs. You'll be lucky if that's the only damage to your engine you have. Change the plugs and then flash to stock and then run that tank down, then fill with much better gas. If you are running 93 tune then try the 91 tune if you see more than 2 degrees or so timing pulls across multiple cylinders in your logs and yes you must log to test if all is well. See the F30 forum for detailed posts on how tolog if don't know how or how to read the logs.
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      09-10-2021, 10:22 PM   #11
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Quote:
Originally Posted by ctt300 View Post
Quote:
Originally Posted by RyanSira View Post
Well guys I think I got it figured out. You were right 100%. Those damn plugs were so melted they weren't even gapped anymore lol. I ordered step 1 colder plugs hoping that fixes the issues completely. Hoping it didn't do any damage from them getting really hot
Hi, you most likely have gas with too low of octane and are getting detonation that melted the plugs. You'll be lucky if that's the only damage to your engine you have. Change the plugs and then flash to stock and then run that tank down, then fill with much better gas. If you are running. 93 tune then try the 91 tune if you see more than 2 or so timing pulls in your logs and yes you must log to test if all is well. See the F30 forum for detailed posts on how tolog if don't know how or how to read the logs.
Well I hope I'm lucky then. New engines are way too much money
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      09-14-2021, 12:28 PM   #12
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Quote:
Originally Posted by RyanSira View Post
Well guys I think I got it figured out. You were right 100%. Those damn plugs were so melted they weren't even gapped anymore lol. I ordered step 1 colder plugs hoping that fixes the issues completely. Hoping it didn't do any damage from them getting really hot

I was not on for a few days and just noticed your reply..

If I understand your post, the plugs were shut closed? If so, that would mean your piston made contact with the plug. As a bare minimum, get or rent a camera scope to look into each chamber. You need to make sure you don't have damaged walls or piston heads.

I am not an expert when it comes to engine internals but it is never a good thing when pistons make contact with a plug tip.

To be on the safe side. Take a recording of each affected cylinder, walls and piston head, and post it up.

Maybe someone with a more thorough background in engines can give it a view and pin point any issues.

Super knock is no joke so I do urge you be on the safe side until everything checks out.

Best of luck
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      09-14-2021, 01:54 PM   #13
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Super knock is super bad. It can break a ringland and damage a cylinder wall. Just one super knock event can do this. The melting of plugs indicates extreme cylinder temps thus the high likelihood for detonation and possibly super knock.

What octane fuel are you running in AK?
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      09-14-2021, 10:49 PM   #14
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I got new spark plugs and gapped them to .022
My car runs like normal again thank god. I'm back on a stock tune right now. If I send a data log is anyone able to look at it for me and tell me if everything looks good? I'm on 90 octane because Alaska doesn't have any better gas available sadly
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      09-15-2021, 12:30 AM   #15
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Here's the log I have. Something to note I had to gap the spark plugs myself so I'm hoping I gapped them all equally. I used the coin gapper. Also I looked at the cylinder with a scope and saw no damage.

https://www.bootmod3.net/log?id=6141...729b7159568870
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      09-15-2021, 04:31 PM   #16
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Quote:
Originally Posted by RyanSira View Post
I got new spark plugs and gapped them to .022
My car runs like normal again thank god. I'm back on a stock tune right now. If I send a data log is anyone able to look at it for me and tell me if everything looks good? I'm on 90 octane because Alaska doesn't have any better gas available sadly
Unless you've got access to E85, you shouldn't be running a Stage II tune then and even a Stage 1 91 tune is full of risk with running 90 octane. The car is designed to run on 91 octane at a minimum. Running higher boost with even lower octane than 91 is dangerous.
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      09-15-2021, 04:35 PM   #17
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Quote:
Originally Posted by XutvJet View Post
Quote:
Originally Posted by RyanSira View Post
I got new spark plugs and gapped them to .022
My car runs like normal again thank god. I'm back on a stock tune right now. If I send a data log is anyone able to look at it for me and tell me if everything looks good? I'm on 90 octane because Alaska doesn't have any better gas available sadly
You shouldn't be running a Stage II tune then and even a Stage 1 91 tune is full of risk.
I'm running ACN 91 stage 2 which is basically 90. The only reason I even had this problem is because I did 4 pulls back to back other than that the car has been running perfect. The computer has some adjustment especially with ACN91 basically being 90
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      09-15-2021, 04:40 PM   #18
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Quote:
Originally Posted by XutvJet View Post
Quote:
Originally Posted by RyanSira View Post
I got new spark plugs and gapped them to .022
My car runs like normal again thank god. I'm back on a stock tune right now. If I send a data log is anyone able to look at it for me and tell me if everything looks good? I'm on 90 octane because Alaska doesn't have any better gas available sadly
Unless you've got access to E85, you shouldn't be running a Stage II tune then and even a Stage 1 91 tune is full of risk with running 90 octane. The car is designed to run on 91 octane at a minimum. Running higher boost with even lower octane than 91 is dangerous.
Almost everyone runs 91 tune up here, only some are custom tuned for 90. My friend has a m240 and he's stage 2 91 and has no problems what's so ever.
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      09-15-2021, 10:50 PM   #19
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Your melted plugs tell the story here. Ultra hot cylinder temps brought on by detonation which is the result low octane. That M240 will likely suffer the same fate. Gapping the plugs isn't going to prevent this issue.

Super knock breaks piston ringlands and on that B58 M240, can destroy the plasma cylinder liner coating. If either of these happens, it's a 5 figure repair. You're walking on egg shells.
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      09-16-2021, 03:14 PM   #20
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pics of plugs?
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      09-18-2021, 07:26 AM   #21
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Quote:
Originally Posted by RyanSira View Post
Here's the log I have. Something to note I had to gap the spark plugs myself so I'm hoping I gapped them all equally. I used the coin gapper. Also I looked at the cylinder with a scope and saw no damage.

https://www.bootmod3.net/log?id=6141...729b7159568870
your car is running LEAN. your hitting like 14 AFR on that brief full throttle. your gonna go boom boom if you keep running that tune on 90 octane fuel. its not even worth it.
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